UC-NRLF 


35    1DD 


EXCHANGE 


ajt:    1 
LCHAKGU 


I. 

The  Detection  and  Determination  of  Minute 
Quantities  of  Glycerine 


II. 


The  Volumes  of  Weight-Normal  Cane  Sugar 
Solutions  at  Different  Temperatures 


DISSERTATION 

SUBMITTED    TO    THE    BOARD    OF    UNIVERSITY    STUDIES    OF 

THE    JOHNS    HOPKINS'    UNIVERSITY    IN    CONFORMITY 

WITH  THE  REQUIREMENTS  FOR  THE   DEGREE 

OF  DOCTOR  OF  PHILOSOPHY. 


BY 

FELTON  SAMUEL  DENGLER, 

BALTIMORE, 

1912 


GEORGE  W.  KING  PRINTING  Co. 
BALTIMORE,  MD. 


I. 

The  Detection  and  Determination  of  Minute 
Quantities  of  Glycerine 


II. 

The  Volumes  of  Weight-Normal  Cane  Sugar 
Solutions  at  Different  Temperatures 


DISSERTATION 

SUBMITTED    TO    THE    BOARD    OF    UNIVERSITY    STUDIES    OF 

THE    JOHNS    HOPKINS    UNIVERSITY    IN    CONFORMITY 

WITH   THE  REQUIREMENTS   FOR  THE    DEGREE 

OF  DOCTOR   OF  PHILOSOPHY. 


BY 

FELTON  SAMUEL  DENGLER, 

BALTIMORE^ 

1912 


GEORGE  W.  KING  PRINTING  Co. 
BALTIMORE,  MD. 


CONTENTS. 

Acknowledgment    5 

I.  The  Detection  and  Determination  of  Glycerine. 

Introduction    7 

A.  Qualitative  Test  7 

Description  of  Method 8 

Results  9 

Conclusions    10 

B.  The  Determination  of  Glycerine. 

Summary  of  Previous  Methods 11 

Description  of  Method 12 

Results   J4 

Results  with  Electrical  Combustion  Method 15 

Summary  and  Conclusions 1G 

II.  The  Volumes  of  Weight-Normal  Cane  Sugar  Solutions. 

Introduction    17 

Description  of  Apparatus 19 

Method 20 

Results 22 

Conclusions    30 

Biography    31 


253953 


ACKNOWLEDGMENT. 

To  Professor  Morse,  under  whose  guidance  this  investigation 
was  pursued,  the  arthur  desires  to  express  his  sincere  gratitude 
for  kindly  assistance  and  instruction.  The  author  is  indebted 
to  President  Ira  Remsen,  Professors  Jones  and  Acree  for  in- 
struction and  inspiration,  also  to  Professor  Whitehead,  under 
whose  guidance  one  of  the  subordinate  subjects  was  carried  out. 

To  Dr.  Frazer  and  Dr.  Holland  the  author's  thanks  are  due 
for  willing  assistance. 


PART  1. 

The  Detection    and   Determination  of  Minute   Quantities   of 

Glycerine. 

In  the  measurement  of  osmotic  pressure  in  this  laboratory, 
no  measurement  is  regarded  as  conclusive  until  it  has  been 
shown  that  the  membrane  was  not  broken,  thereby  allowing 
some  of  the  solution  to  escape  from  the  cell.  In  other  words, 
the  solution  whose  osmotic  pressure  is  being  measured  must 
have  the  same  concentration  after  the  cell  has  been  up  days, 
or  in  some  cases  weeks,  as  it  had  when  it  was  first  put  up. 
There  are  two  ways  of  solving  this  problem.  Either  the  solu- 
tion on  the  inside  of  the  cell  must  be  tested  before  and  after  the 
experiment,  to  ascertain  whether  or  not  any  dilution  has  taken 
place,  or  the  solution  on  the  outside  of  the  cell  must  be  tested 
to  ascertain  whether  or  not  it  contains  any  of  the  substance 
whose  osmotic  pressure  is  being  measured. 

The  polarimeter  affords  an  excellent  method  for  substances 
which  are  optically  active,  but  in  the  case  of  glycerine,  it  was 
thought  more  practicable  to  test  the  water  in  which  the  cell  is 
immersed  for  the  presence  of  this  substance.  It  was  necessary 
to  search  for  some  methods  for  the  detection  and  determination 
of  minute  quantities  of  this  substance. 

Qualitative  Test. 

In  the  measure  of  osmotic  pressure,  it  is  the  practice  here  to 
make  the  water  in  which  the  cell  is  immersed  during  measure- 
ment, one-hundredth  ion  weight  normal  with  copper  sulphate; 
while  to  the  solution  on  the  inside  of  the  cell,  there  is  added, 
besides  the  substance  whose  osmotic  pressure  is  to  be  deter- 
mined, a  quantity  of  potassium  ferro  cyanide,  which  is  osmoti- 
cally  equivalent  to  the  copper  sulphate  on  the  outside.  The 
purpose  of  the  addition  of  these  membrane-forming  salts,  is  to 


8 

repair  any  break  which  may  occur  in  the  membrane.  If  there 
is  added  to  an  alkaline  solution  of  glycerine,  a  small  quantity 
of  copper  sulphate,  the  solution  becomes  deep  blue  in  color,  but 
without  precipitation  of  cupric  hydroxide.  If  the  addition  of 
copper  sulphate  is  continued,  the  precipitate  of  cupric  hydro- 
xide appears.  The  color  is  very  similar  to  the  color  of  solutions 
containing  the  Cu  (NH3)4  ion. 

The  cupric  hydroxide  can  be  filtered  off  through  an  asbestos 
filter,  although  some  of  the  colored  copper  glycerine  compound 
is  absorbed  by  the  asbestos  in  the  filtering  process.  Because 
this  absorbtion  takes  place,  the  method  cannot  be  used  for  the 
quantitative  determination  of  small  quantities  of  glycerine 
colorimetrically. 

It  was  a  question  whether  or  not  this  color  might  be  due  to 
the  alkali  dissolving  some  of  the  copper,  hence  the  experiments 
tabulated  below  were  carried  out  to  determine  at  what  concen- 
tration the  alkali  dissolves  the  copper.  Column  2  shows  the 
quantities  of  copper  sulphate ;  column  3,  the  quantities  of  gly- 
cerine; column  4,  the  quantities  of  potassium  hydroxide;  col- 
umn 5,  the  total  number  of  cubic  centimeters  in  the  ;final  solu- 
tion; column  6,  is  the  normality  of  the  alkali  obtained  from 
columns  4  and  5,  and  column  7  shows  the  color  of  the  filtrate. 


>% 

-  5 

5s 

j>  2 

H  o 

1 

24.78 

5 

28.05 

21 

2 

24.78 

5 

280.50 

30 

3 

24.78 

5 

420.75 

•   35 

4 

24.78 

5 

504.90 

38 

5 

24.78 

5 

701.25 

45 

6 

24.78 

0 

701.25 

45 

7 

24.78 

0 

701.25 

45 

8 

24.78 

0 

420.75 

35 

9 

24.78 

0 

504.00 

38 

10 

24.78 

0 

561.00 

40 

11 

49.56 

5 

T04.90 

38 

12 

49.5(5 

0 

504.90 

38 

.023 

no  color 

.170 

slight  color 

.210 

slight  color 

.240 

good  color 

.280 

deep  color 

.280 

slight  color 

.280 

slight  color 

.210 

no  color 

.240 

no  color 

very 

.250 

slight  color 

.240 

good  color 

.240 

no  color 

9 

A  study  of  the  table  shows  that  in  the  first  five  experiments, 
as  the  concentration  of  the  alkali  increases — the  quantities  of 
all  the  other  substances  being  kept  constant — from  .23  normal 
to  .28  normal,  the  color  of  the  filtrate  increases.  Experiments 
Nos.6  and  7,  which  contain  no  glycerine,  show  by  the  slight  color 
of  the  filtrate  that  some  of  the  copper  has  been  dissolved.  In  ex- 
periments 8  and  9,  in  which  the  concentration  of  the  alkali  was 
.21  and  .24  normal,  respectively,  no  color  was  obtained  in  filtrate, 
while  in  experiment  No.  10,  when  the  alkali  was  .25  normal,  a 
very  slight  color  was  obtained  in  the  filtrate. •'_  Some  of  the  cop- 
per is  dissolved  then  when  the  alkali  is  .25  normal,  but  it  is  not 
dissolved  if  the  alkali  is  kept  at  .24  normal,  or  below.  In  other 
words,  the  solution  in  wrhich  this  reaction  is  employed  for  the 
detection  of  glycerine  must  not  be  over  .24  normal  with  potas- 
sium hydroxide. 

The  following  experiments  were  carried  out  with  the  view  of 
determining  how  small  quantities  of  glycerine  could  be  de- 
tected : 


w  .  Sw 

Otc  oo 


Sg 

r  g 

X£ 

—     -  ) 

t~ 

E-  1 

'T 

N 

5 

123.92 

100 

1262.25 

.23 

100 

colored 

X 

3 

123.92 

100 

1262.25 

.23 

100 

colored 

N 

2 

123.92 

100 

1262.25 

.23 

100 

colored 

N 

1 

123.92 

100 

12(52.25 

.23 

100 

colored 

N 

0 

123.92 

100 

1262.25 

.23 

100 

colorless 

These  show  that  one  milligramme  of  glycerine  can  be  detected 
in  one  hundred  cubic  centimeters  of  solution.  The  filtrate  of 
the  blank  containing  no  glycerine  is  colorless,  therefore  the  color 
in  the  other  experiments  can  not  be  due  to  dissolve)  copper. 

Some  idea  of  the  composition  of  the  copper-glycerine  com- 
pound was  obtained  by  mixing  copper  sulphate  and  glycerine  in 
different  proportions,  molecule  for  molecule.  If  all' the  copper 


10 

is  used  up  by  the  glycerine  in  forming  the  colored  compound, 
then  no  precipitate  of  cupric  hydroxide  will  be  formed.  A  pre- 
cipitate then  indicates  that  more  copper  is  present  than  is  neces- 
sary for  the  formation  of  the  colored  compound. 


,.  - 

F    .         ^    .  £•-          2 

1  mol.  -lye.  10  %  mol. 

(T  SO  4 ~ 2        2.71        .23        100     Slight  color  and  no  ppt. 

1  mol.  glye.  to  %  inol. 

CU  SO  4 .'>         4.07         .23         300     <loo<l  color  ;nul  no  ppt. 

1  mol.  glyc.  to  1  mol. 

CU  SO  4 :•>        s.i:j        .2:',        100    Good  color  and  a  ppt. 

1  mol.  glyc.  to  1  mol. 

CU  SO  4 100     271.2  .2:5         100     Deep  blue  color  and  ppt. 

1  inol.  glyc.  to  1/2  mol. 

CU  SO  4 100     135.62        .23        100     Deep  blue  color  and  no 

ppt. 

The  experiments  show  that  when  the  ratio  is  one  molecule  of 
glycerine  to  one-half  molecule  of  copper  sulphate,  or  rather  two 
molecules  of  glycerine  to  one  molecule  of  copper  sulphate,  then 
all  the  copper  remains  in  solution.  The  conclusion  to  be  drawn 
from  these  facts  is  that  the -copper  atom  substitutes  two  hydro- 
gen atoms,  each  in  diflfierent  molecules  of  glycerine,  and  thus 
serves  to  hold  together  two  glycerine  residues.  The  logical  way 
to  carry  out  these  experiments  would  be  to  add  the  copper  sul- 
phate solution  drop  by  drop  to  the  alkaline  glycerine  solution 
until  one  drop  produces  a  precipitate  of  cupric  hydroxide. 
This  was  tried,  but  a  precipitate  appeared  before  the  ratio 
reached  iwo  molecules  of  glycerine  to  one  molecule  of  copper 
sulphate.  It  would  appear  then  that  some  of  the  copper  was 
used  up  by  the  alkali  to  form  cupric  hydroxide  before  all  the 
glycerine  had  been  changed  to  the  colored  compound.  (_The 
alkali  must  then  be  added  last  to  the  solution  containing  the 
copper  sulphate  and  the  glycerine. 

The  qualitative  test  can  then  be  used  for  detecting  two  or 
three  milligrammes,  and  with  some  experience,  one  milligramme 
of  glycerine  in  one  hundred  cubic  centimeters  of  solution.  The 


11 

unknown  solution  should  contain  enough  copper  sulphate  to 
make  it  one-hundredth  normal,  and  enough  alkali  is  then  added 
to  make  I  lie  solution  .lio  normal.  The  precipitate  of  cupric 
hydroxide  is  tillered  off,  and  if  the  filtrate  has  a  blue  color,  the 
solution  contained  glycerine,  provided  other  substances  are 
absent  which  behave  in  the  same  way. 

Quantitative  Detenu  inn  I  ion. 

The  estimation  of  glycerine  can  be  affected  by  oxidation  with 
potassium  permanganate  or  potassium  diehromate.  Hehners1 
dichroiuate  method,  in  which  the  amount  of  that  salt  reduced  is 
determined,  has  this  objection,  that  since  the  standard  solution 
is  somewhat  strong  and  expands  as  much  as  .05  per  cent,  per 
degree,  great  care  must  be  taken  to  keep  the  temperature  con- 
stant, and  at  best,  the  method  does  not  permit  any  great  re- 
finement and  was  wholly  inapplicable  to  our  purpose. 

The  permanganate  oxidation  method  was  first  proposed  by 
Wauklynr'and  further  worked  by  Fox,  Benedikt  and  /sigmondy.2 
The  following  is  a  brief  statement  of  the  same:  The  glycerine 
solution  is  made  alkaline  with  potassium  hydroxide  and  then 
treated  with  a  saturated  solution  of  permanganate.  The  solu- 
tion is  boiled  one  hour  and  then  treated  with  enough  sodium  sul- 
phite to  destroy  the  excess  of  permanganate.  The  precipitated 
manganese  dioxide  is  filtered  oil.  and  known  volumes  of  (lie  fil- 
trate are  acidified  with  acetic  acid  and  then  treated  with  calcium 
chloride.  The  precipitated  calcium  oxalate  is  either  determined 
gravimetric-ally  as  the  carbonate  or  the  precipitate  is  rinsed 
from  the  filter,  acidified  with  sulphuric  acid,  heated  to  60  de- 
grees ( \  and  titrated  with  a  decinorijnal  solution  of  perman- 
gamite.  The  authors  of  the  method  obtained  satisfactory  re- 
sults with  it,  but  it  is  long  and  rather  complicated.  The 
method  was  likewise  inapplicable  where  very  minute  quanti- 
ties of  glycerine  were  to  be  determined. 


1.  Allan's  roininrn-inl  (>rir:mir  Chemistry.     Vol.  2.  316. 

2.  Allen's  ( '<>mni<>rci;il  (M-i;;Mii<-  ( 'hemisfry.     Vol.  2.  .",14. 


12 

The  following  work  was  undertaken  then  to  adapt  the  oxi- 
dation by  permanganate  to  our  conditions.  The  standard  solu- 
tion of  potassium  permanganate  employed  contained  from  five 
to  six  milligrammes  of  the  dissolved  salt  in  each  cubic  centi- 
meter. A  standard  solution  of  potassium  tetroxalate,  which 
was  used  in  determining  the  strength  of  the  permanganate,  was 
made  equivalent,  as  nearly  as  possible,  to  the  permanganate 
solution. 

Solutions  of  potassium  permanganate  are  not  stable  and  often 
deteriorate  very  rapidly  because  of  the  reduction  caused  by 
small  quantities  of  the  oxides  of  manganese.  v>  The  best  results 
were  obtained  by  preparing  the  permanganate  solution  in  the 
following  way:  The  approximate  amount  of  the  salt  is  dis- 
solved in  water  and  allowed  to  stand  in  the  dark  for  several 
days.  This  gives  a  chance  for  the  oxidation  of  any  oxidizable 
substance,  and  also  any  precipitated  oxides  are  coagulated. 
The  solution  is  then  filtered  through  two  connected  asbestos 
filters.  The  filtrate  is  then  allowed  to  stand  for  several  more 
days  and  then  filtered  by  the  same  process  into  a  clean  bottle. 
The  necessary  amount  of  water  can  then  be  added.  Solutions 
prepared  in  this  way  can  be  kept  two  weeks  or  more  without 
any  appearance  of  oxide  or  any  deterioration. 

The  potassium  tetroxalate  was  prepared  in  the  usual  way. 
A  saturated  solution  of  oxalic  acid  was  divided  into  two  parts. 
The  smaller  part  was  one-fourth  of  the  whole,  less  about  two  or 
three  cubic  centimeters.  The  smaller  portion  was  neutralized 
with  potassium  carbonate  while  boiling.  The  larger  portion 
was  then  heated  and  the  potassium  oxalate  stirred  in.  The 
crystals  obtained  are  then  recrystalized  twice  from  water  and 
dried  on  porous-  plates. 

All  the  oxidation  experiments  were  carried  out  in  alklinc 
solutions.  The  solutions  also  contained  enough  copper  sulphate 
to  make  them  one-hundredth  normal  with  respect  to  that  sub- 


13 

stance.  Preliminary  experiments  were  necessary  to  determine 
the  time  and  temperature  necessary  for  the  complete  oxidation. 
The  best  results  were  obtained  by  keeping  the  solutions  for 
nineteen  hours  in  a  constant  temperature  bath  regulated  at  50 
degrees  C.  Increasing  the  time  did  not  increase  the  amount  of 
permanganate  reduced. 

An  experiment  was  carried  out  in  the  following  way:  To  an 
alkaline  solution  of  copper  sulphate  and  glycerine,  a  consider- 
able excess  of  standard  potassium  permanganate  solution  is 
added.  This  is  then  allowed  to  stand  in  the  50  degree  bath  for 
nineteen  hours.  To  this  is  then  added  potassium  tetroxalate 
equivalent  to  the  amount  of  potassium  permanganate  used. 
The  solution,  after  reduction,  is  then  acidified  with  sulphuric 
acid,  healed  to  60  degrees  C.,  and  titrated  with  potassium  per- 
manganate solution  until  a  pin,k  color  is  obtained.  The  amount 
of  potassium  permanganate  used  in  titrating  is  equivalent  to 
the  amount  of  potassium  permanganate  reduced  by  the  gly- 
cerine. The  number  of  atoms  of  oxygen,  equivalent  to  the 
amount  of  potassium  permanganate  reduced,  was  then  calcu- 
lated, and  from  this  the  number  of  atoms  of  oxygen  per  mole- 
cule of  glycerine  determined.  Blank  experiments  were  put  in 
every  day,  which  were  in  every  respect  identical  with  the  other 
experiments,  except  that  they  contained  no  glycerine.  By 
means  of  these  blank  experiments  any  reduction  outside  of  that 
produced  by  the  glycerine  itself,  could  be  detected  and  they  also 
serve  as  a  check  on  the  strength  of  the  potassium  permanganate 
solution.  In  every  instance  where  a  reduction  had  apparently 
faken  place  in  these  blank  experiments,  it  was  found  that  the 
potassium  permanganate  solution  had  deteriorated. 

The  following  oxidation  experiments  were  all  kept  in  a  50 
degree  constant  temperature  bath  for  nineteen  hours.  The  re- 
sults are  calculated  in  terms  of  the  number  of  atoms  of  oxygen 
per  molecule  of  glycerine.  The  theoretical  number  of  atoms  of 
oxygen  necessary  to  oxidise  a  molecule  of  glycerine  to  carbon 
dioxide  and  water  is  seven. 


14 


a 


1 

1 

123.9 

140 

24X.73 

5.29 

5.29 

7.68 

2 

1 

123.9 

140 

248.73 

5.47 

5.47 

7.96 

3 

2 

123.9 

140 

248.75 

9.33 

4.6(5 

6.79 

4 

2 

123.9 

140 

248.75 

9.3:5 

4.66 

6.79 

5 

g 

123.9 

140 

248.T) 

23.63 

4.73 

6.87 

6 

5 

123.9 

140 

248.75 

24.06 

4.81 

7.00 

7 

10 

123.9 

140 

24S."5 

4(5.76 

4.66 

6.80 

8 

10 

123.9 

140 

248.75 

46.64 

4.66 

6.79 

9 

25 

123.9 

140 

20.75 

117.17 

4.69 

6.X  1 

10 

25 

123.9 

140  ' 

24S."5 

1H5.7X 

4.157 

(5.79 

11 

30 

123.9 

140 

249.40 

141.04 

4.70 

6.84 

12 

30 

123.9 

140 

249.40 

140.47 

4.68 

6.82 

13 

30 

123.9 

140 

249.40 

140.85- 

4.70 

6.84 

14 

40 

123.9 

140 

311.75 

1X5.78 

4.64 

•  5.7(5 

15 

40 

123.9 

140 

311.75 

1X5.97 

4.65 

(5.77 

16 

40 

123.9 

140 

311.75 

187.45 

4.69 

(5.X2 

17 

50 

123.9 

140 

446.01 

234.79 

4.70 

<;.X4 

18 

50 

123.9 

140 

446.01 

235.75 

4.71 

6.86 

19 

50 

123.9 

140 

446.01 

i):>,3,84 

4.68 

6.83 

20 

48.5 

123.9 

140 

498.80 

224.46 

4.63 

6.74 

Mean 

4.69 

6.82 

Colniuiis  1\  .')  and  4  show  the  (quantities  of  glycerine,  copper 
sulphate  and  alkali  in  each  experiment.  Column  5  shows  the 
quantity  of  permanganate  added  for  the  oxidation  of  the  gly- 
cerine. A  large  excess  of  permanganate  must  be  added,  since 
in  alkaline  solution,  only  one  and  a  half  atoms  of  oxygen  per 
molecule  of  permanganate  are  available  for  oxidizing  the  gly- 
cerine. )  Column  6  shows  the  amount  of  permanganate  reduced 
by  the  quantity  of  glycerine  in  column  1.  Column  7  gives  the 
milligrammes  of  permanganate  reduced  by  each  milligramme  of 
glycerine.  Column  8  gives  the  number  of  atoms  of  oxygen  for 
each  molecule  of  glycerine  calculated  from  the  quantity  of 
permanganate  reduced,  and  the  quantity  of  glycerine  present. 

The  mean  values  do  not  include  experiments  1  and  2. 
where  only  1  milligramme  of  glycerine  was  oxidized.  The  mean 
number  of  atoms  per  molecule  of  glycerine  is  0.82,  while  the 
theoretical  number  is  seven.  Two  different  solutions  of  gly- 
cerine were  used  in  these  experiments,  one  containing  one  milli- 


IS 

gramme  of  glycerine  per  cubic  centimeter  of  solution,  and  the 
other  contained  five  milligrammes  of  glycerine  per  cubic  centi- 
meter of  solution,  so  that  it  was  unlikely  there  was  an  error  in 
making  up  the  glycerine  solution.  As  a  further  check  on  the 
glycerine  solution  in  experiment  No.  20,  a  weighed  amount  of 
glycerine  was  oxidized  directly  with  practical  agreement.  In 
experiments  Nos.  1  and  -.  the  results  obtained  are  high  com- 
pared with  others.  This  is  probably  due  to  the  experimental 
errors,  including  the  temperature,  effects  on  standard  solutions, 
which  are  often  considerable,  accumulating  on  the  small  quan- 
tity of  glycerine. 

In  view  of  the  fact  that  all  the  results  obtained  are  below 
in  the  amount  of  oxygen  necessary  to  oxidize  the  glycerine  to 
carbon  dioxide  and  water,  it  seemed  desirable  to  check  this 
method  by  some  other  method.  It  was  first  proposed  to  oxidi/e 
the  glycerine  with  chromic  acid,  and  collect  the  carbon  dioxide 
gas  formed,  and  in  this  way  determine  the  purity  of  the  gly- 
cerine. This  method  did  not  work  out,  as  the  chromic  acid 
seemed  to  absorb  the  carbon  dioxide,  and  the  results  were1  lower 
than  those  obtained  by  the  potassium  permanganate  method. 

The  electrical  method  for  the  combustion  of  organic  sub- 
stances devised  by  Morse,  Taylor  and  (iray1  was  then  used.  The 
glycerine  was  burned  in  a  current  of  heated  oxygen.  The  oxy- 
gen is  heated  by  passing  through  a  porcelain  tube  around  which 
a  platinum  wire  is  coiled,  and  which  wire  carries  a  current  of 
electricity.  The  results  of  five  combustions  are  contained  in 
the  following  table : 


II 


98.0 

137.7 

:5s.:u8 

37.55] 

0/767 

6.85 

81.0 

112.4 

31.67] 

:;<).(  ;r,t 

1.020 

0.78 

74.  !» 

103.7 

29.286 

28.279 

1.007 

o.76 

80.2 

112.8 

31.358 

30.76] 

.598 

6.87 

87.] 

122.3 

34056 

:;:  1.351 

.70.". 

r,.sc, 

Mcan=s= 

(5.82 

1.     Morse,  "Exercises  in  Quantitive  Chemistry."  ]>;iir«>  r.:;7 


16 

The  results  obtained  then  by  the  potassium  permanganate 
and  electrical  combustion  methods  agree,  and  the  glycerine 
used  has  a  purity  of  97.29%.  The  glycerine  oxidized  by  the  per- 
manganate was  therefore  only  97.29  per  cent  pure.  If  we  apply 
this  correction  to  6.S2,  the  mean  number  of  atoms  of  oxygen 
which  appear  to  be  used  by  a  molecule  of  glycerine,  we  get  7.01 
atoms  of  oxygen  per  molecule  of  glycerine,  while  the  theoreti- 
cal number  is  seven.  Glycerine  is  very  hydroscopic,  and  in  all 
operations  care  was  taken  so  that  the  substance  was  exposed  as 
little  as  possible  to  the  moisture  of  the  air. 

The  potassium  permanganate  oxidation  method  then  can  be 
used  for  determining  quantities  of  glycerine  as  small  as  two 
milligrammes  in  alkaline  copper  sulphate  solutions. 

The  solutions  inside  and  outside  the  cell  are  in  ordinary 
practice,  made  one-thousandth  normal  with  thymol  to  prevent 
the  growth  of  penicillium  in  the  sugar  solutions.  If  the  potas- 
sium permanganate  method  is  used  for  the  quantitative  deter- 
mination of  the  glycerine,  some  other  way  of  destroying  the 
penicillium  will  have  to  be  devised.  The  thymol  is  readily  oxi- 
dized by  the  permanganate,  and  the  amount  of  permanganate 
reduced  by  the  thymol  would  be  large  compared  to  the  amount 
reduced  by  glycerine,  so  that  all  the  experimental  errors  would 
accumulate  on  the  relatively  small  quantity  of  that  substance. 


PART  2. 

of  Wcif/Jit  Xornuil  Cam'  fruyar  Solutions  at  Different 
Temperatures.1 


When  a  solid  substance  is  dissolved  in  a  liquid,  the  volume  of 
the  solution  is  not  equal  to  the  sum  of  the  volumes  of  the  solute 
and  solvent,  but  is  usually  smaller.  This  shrinkage  is  often 
quite  large,  and  in  the  case  of  weight  normal  solution  of-  glucose, 
it  was  found  by  Morse,  Frazer  and  Dunbar2  to  be  6.03  cubic  cen- 
timeters, when  178.74  grams  of  glucose  are  dissolved  in  1,000 
grams  of  water  at  0  degrees.  The  exact  nature  of  the  cause  of 
this  contraction  is  not  known. 

This  investigation  was  undertaken  with  the  view  of  deter- 
mining the  contraction  in  cane  sugar  solutions  at  different  tem- 
peratures. It  was  proposed  to  measure  the  increase  in  volume 
directly  in  going  from  a  lower  to  a  higher  temperature.  In  other 
words,  the  apparatus  was  to  be  of  the  dilatometer  rather  than 
the  pycnometer  type.  With  this  in  view,  an  apparatus  illus- 
trated in  Figure  1  was  devised. 

It  consists  essentially  of  a  bulb  and  a  calibrated  tube  "ab," 
in  which  the  increase  in  volume  is  read  with  the  cathetometer. 
The  stop  cock  is  placed  at  the  bottom  for  convenience  in  clean- 
ing and  drying  the  apparatus.  It  also  has  the  advantage  that 
no  small  gas  bubbles  can  collect  there  when  the  temperature  is 


1.  This  work  was  clone  in  collaboration  with  Mr.  Eyssell,  and  all  the 
data  on  the  odd  concentrations  will  be  found  in  his  dissertation. 

2.  Am.  Chem.  Journal,  38,  222. 


1 


100 

cc 


F  ic  i 


19 

raised,  which  might  happen  were  it  placed  on  the  side  or  near 
the  top.  It  is,  of  course,  necessary  that  the  stop  cock  fit  per- 
fectly, and  considerable  grinding  was  necessary  in  order  to  ob- 
tain the  desired  result. 

The  bulb  part  and  the  capillary  tube  "ab"  are  prepared  sepa- 
rately and  then  sealed  at  "c."  The  bulb  is  weighed  empty. 
Tt  is  then  filled  with  air-free  water  of  known  temperature  to  the 
0  mark  on  Ihe  tube  and  weighed.  It  is  then  filled  with  water  of 
a  known  temperature  to  the  100  mm.  mark,  and  again  weighed. 
From  the  weights  and  temperatures  of  the  water,  the  capacity 
of  the  bulb  to  0  mark  and  of  the  tube  from  0  to  100mm.  can  be 
calculated.  The  small  tube  "ab"  .has  an  internal  diameter  of 
2-2.25  nun.,  and  the  distance  between  the  scratches  "a"  and  "b" 
is  approximately  350  mm.  The  part  between  the  scratches  was 
carefully  calibrated  by  means  of  a  short  thread  of  mercury,  and 
a  curve  drawn  for  the  corrections  which  must  be  applied  on 
account  of  the  inequalities  of  the  bore.  The  calibrated  tube 
was  then  sealed  on  to  the  graduated  tube  at  "c."  The  capacity 
between  the  100  mm.  mark  and  the  lower  scratch  "a"was  deter- 
mined by  means  of  a  mercury  thread  which  rested  on  the  100 
inni.  mark  and  extended  above  scratch  "a"  into  the  cali- 
brated part  of  the  tube.  The  thread  was  weighed  and  its 
volume  calculated  at  the  temperature.  The  known  volume  of 
the  portion  of  the  tube  above  the  scratch  "a"  which  is  filled  by 
the  mercury,  is  then  deducted  from  the  total  volume.  The  dif- 
ference, after  applying  the  meniscus  correction,  is  the  capacitv 
of  the  apparatus  between  "a"  and  the  upper  limit  of  gradu- 
ation. All  weighings  were  made  with  a  tare  of  the  same  volume 
and  form,  so  that  the  weighings  were  not  influenced  by  tempera- 
ture, moisture  or  air  displaced.  In  all,  eleven  such  pieces  of 
apparatus  were  prepared  so  that  ten  could  be  used  for  the  fe  ; 
weight  normal  cane  sugar  solutions,  and  the  eleventh  for  air 
free  wafer. 

The  water  used  in  making  up  the  cane  sugar  solutions  was 
boiled  to  free  if  from  air.  Tn  making  up  a  solution,  the  quantity 
of  water  was  taken,  which  in  a  vacuum,  would  weigh  150  grams. 


20 

To  this  was  added  the  necessary  weight  of  cane  sugar,  also  cor- 
rected for  air  displaced.  The  rotation  of  the  solution  was 
taken  with  a  polarimeter  as  a  check  on  the  concentration.  The 
rotation  was  also  taken  after  the  experiment,  in  order  to  deter- 
mine whether  any  increase  or  loss  of  concentration  had  taken 
place.  The  cane  sugar  solution  was  cooled  below  the  tempera- 
ture of  the  bath  in  order  that  there  might  be  an  increase  rather 
than  a  decrease  in  volume  in  reaching  the  temperature  of  the 
bath.  A  decrease  in  volume  would  mean  the  leaving  of  a  film  of 
solution  on  the  walls  of  the  calibrated  tube,  and  the  exact 
volume  would  necessarily  be  diminished  by  that  amount.  The 
top  of  the  calibrated  tube  was  closed  by  means  of  a  rubber  cap 
used  in  fountain  pen  fillers.  This  cap  effectually  prevented 
any  evaporation,  and  at  the  same  time  allowed  for  any  ex- 
pansion. 

The  temperature  of  the  hydrant  water  during  April,  made  it 
necessary  to  give  up  all  the  temperatures  below  15  degrees. 
The  pieces  of  apparatus  were  weighed  empty,  filled  with  the 
solutions,  and  placed  in  a  constant  temperature  bath  regulated 
automatically  to  keep  the  desired  temperature  with  a  maximum 
variation  of  about  .01  of  a  degree.  A  description  of  the  bath 
used  will  be  found  in  Vol.  45  of  the  American  Chemical  Journal, 
page  381.  Several  days  were  required  for  the  solutions  and 
glass  to  come  to  temperature,  after  which  constant  readings 
were  obtained  on  the  height  of  the  liquid  in  the  calibrated  tube. 
After  the  volumes  of  the  solutions  had  remained  constant  for 
several  days  and  the  necessary  readings  secured,  the  bath  was 
regulated  to  the  next  desired  higher  temperature.  In  this  work, 
the  volumes  were  determined  at  15,  20,  25,  and  30  degrees.  The 
pieces  of  apparatus  were  then  taken  down  and  weighed  with 
the  contained  solution.  From  the  weight  of  the  apparatus, 
empty  and  full,  the  weight  of  the  solution  is  obtained.  This 
weight  must  be  corrected  for  the  weight  of  the  solution 
contained  in  the  bore  of  the  stop  cock,  since  this  solution  in  the 
stop  cock  did  not  enter  into  the  volume  changes.  The  correc- 
tion was  applied  as  follows:  The  volume  of  the  bore  of  the 
stop  cock  was  determined  by  means  of  mercury.  This  volume 


21      . 

was  then  added  to  the  observed  volume  of  the  whole  solution  at 
'20  degrees.  The  weight  of  the  solution,  divided  by  this  cor- 
rected volume,  gives  the  density  of  the  solution.  The  density 
times  the  volume  of  the  bore  of  the  stop  cock,  gives  the  weight 
of  the  solution  in  the  stop  cock,  and  this  weight,  subtracted 
from  the  original  weight,  gives  the  corrected  weight  of  the 
solution  in  the  tube.  In  the  following  table  1,  column  1,  con- 
tains the  number  of  the  pieces  of  apparatus;  colume  2,  the 
weight  normal  concentration  of  the  solution;  column  3,  the 
volume  of  the  bore  of  the  stop  cock ;  column  4,  the  density  of  the 
solution ;  column  5,  the  weight  of  the  solution  in  the  bore,  and 
column  6,  the  corrected  weight  of  the  solution  in  the  apparatus. 


TABLE  1. 

1 

n 

3 

4 

5 

6 

| 

J. 

_. 

6  6 

^  J 

§ 

b»§ 

Hj 

§   j 

II 

fill 

E 

^  2 

3  -  x 

J  -~ 

>^~ 

o  "3  3  § 

^ 

^  — 

r"*"  —    ^ 

—  v.  r. 

w  £  x  rt 

7 

0.2 

.0510 

1.0228 

.0522 

102.6412  g. 

13 

0.4 

.0576 

1.0458 

.0602 

105.1192  g. 

6 

0.6 

.0393 

1.0663 

.0419 

107.2322  g. 

10 

0.8 

.0472 

1.0869 

.0513 

109.2404  g. 

15 

1.0 

.0461 

1.1048 

.0509 

110.9894  g. 

Water          .0452  0.9972  .0451  100.2209  g. 

In  order  to  calculate  the  volume  of  the  sugar  used  in  making 
up  the  solutions,  the  specified  gravity  of  solid  sugar  must  be 
known.  On  looking  this  up,  a  wide  variation  was  found  in  the 
results  obtained  by  different  investigators.  It  was  difficult  to 
decide  on  which  one  was  correct,  so  it  was  decided  to  work  out 
two  tables  for  each  temperature,  one  using  the  value  1.5813,  ob- 
tained independently  by  Kopp  and  Gerlack,  and  the  other  table 
based  on  the  value  1.5860  obtained  by  Schroeder.  Joule  and 
Playfair  give  .0001116  per  degree  as  the  cubical  expension  of 
solid  sugar  between  0  and  100  degrees. 

The  volume  of  1,000  grams  of  water  at  the  desired  tempera- 
ture was  calculated  from  the  values  found  in  Landolt-Boern- 
stein-'s  Physikalisch-Chemiscbe  Tabellen. 


22 

The  actual  volume  of  a  sugar  solution,  containing  1,000  grams 
of  water,  was  calculated  from  the  observed  volume  and  the  per- 
centage of  water  by  weight  in  that  volume.  The  following 
table  2  gives  the  percentage  by  weight  of  sugar  and  water  in 
the  different  concentrations  of  weight  normal  sugar  solutions. 

TABLE  -2. 


^  c 

f-  ? 

—  ? 

^  V. 

i.  v. 

0.2 

tooo 

0:5.65 

(57.8784 

6.85 

0.4 

1000 

88.05 

135.7568 

1  1  .05 

0.6 

1000 

83.08 

203.6352 

1(5.02 

0.8 

1000 

78.65 

271.5136 

21.35 

1.0 

1000 

74.66 

339.3020 

25.34 

The  results  obtained  at  15  degrees  are  given  in  the  two  fol- 
lowing tables.  For  calculating  the  volumes  of  the  sugar  1.5813 
was  used  as  the  specific  gravity  of  solid  sugar  in  table  3  and 
1.5860  was  used  in  table  4. 

TABLE  :;. 
Temperature  15  degrees.     Sp.  (Jr.  of  solid  sugar  =  1.5X13. 

o  *  S  . 

I         *  o  e..a-  ;-" 


0-43  & 
CS   V- 


5. 


£1 


0.2 
0.4 

0.6 
0.8 
1.0 

1000.857 
1000.857 
1000.857 
1000.857 

1000.857 

42.024 

85.848 
12X.772 
171.696 
214.620 

1043.781 
1086.705 
11  29.62!  > 
1172.553 
1215.477 

1042.940 
1084.756 
1127.430 
1168.358 

1210.672 

0.832 
1.949 
2.190 
4.195 

4.805 

TABLE  4. 

Temperature  15  decrees.     Sp.  Gr.  of  solid  sugar  =  1.5860. 


f| 

"OCJ  - 

II 

a*TJ 

1.2 

kj| 

^  c 

'^  -J 

•»*  V. 

ac-'S  § 

c  > 

—  > 

0.2 

1000.857 

42,788 

1048.645 

1042.040 

0.60(5 

0.4 

1000.857 

X5.576 

1086.438 

1084.75<; 

1  .677 

0.6 

1000.857 

128.364 

1129.221 

1127.430 

1.782 

0.8 

1000.857 

171.152 

1172.009 

1168.358 

3.651 

1.0 

1000.857 

213.940 

1214.70  -t 

1210.672 

4.125 

23 

Tables  .")  and  (i  contain  I  lie  results  obtained  at  -0  degrees. 

TABLE  5. 
Temperature  20  delves.     Sp.  (Jr.  of  solid  sugar  =  1.5X13. 


•i. 

c 

g 

•-r 

-r 

I* 

Q 

88 

~=L~ 

~  ._. 

|   . 

®-gg 

^S 

:~~ 

it  Z 

E  ^T 

Z-  C 

^  ^ 

in  /- 

-  :r 

~  :: 

"3  ^f 

•3  *4  C 

.£  "E 

^r  "5 

^  — 

'^>  > 

'^  7 

*/:  c  S 

—  -    > 

.—  ^ 

0.2 

1001.7.",! 

42.94s 

1044.699 

1044.007 

0.692 

0.4 

1001.751 

sr,.896 

1087.647 

1065.1*74 

1.673 

0.6 

1001.7."! 

128.844 

1130.595 

112S.806 

1.789 

0.8 

1001.751 

171.792 

1173.543 

1  ir.ii.S77 

3.666 

1.0 

1001.751 

214.740 

1216.41)1 

1212.343 

4.148 

TABLE  6. 

Temperature 

20  degrees. 

Sp.  Gr.  of  solid 

sugar  = 

1.5860. 

w 

«; 

c 

e 

<M 

c 

O  ^ 

r 

0 

c 

^*         " 

r^ 

^j  O 

-LJ  — 

ffi 

9) 

•—  ^  ':/. 

>  c; 

?.£ 

•r  5 

r  &.' 

2  «- 

ts  S 

^  5 

?" 

•r  F 

£  ~ 

-r  ?r 

i  ^~ 

I  — 

fc^ 

>  3 

'^  i; 

•^  7 

00  ^S 

~  >~ 

—  > 

0.2 

1001.751 

42.812 

1044.563 

1044.007 

0.556 

0.4 

1001.751 

85.624 

1087.375 

1085.974 

1.401 

0.6 

100li751 

128.436 

1130.187 

1128.806 

1.381 

0.8 

1001.751 

171.248 

1172.999 

1169.877 

3.122 

1.0 

1001.751 

214.060 

1215.811 

1212.343 

3.468 

Tables  7  and  8 

contain  the 

results  obtained  at  25 

degrees. 

TABLE  7. 

Temperature 

25  degrees. 

Sp.  Gr.  of  solid 

sugar  = 

1.5813. 

c 

X 

"o 

*-4 

C 

*G 

c 

"*  •    e£ 

t3 

V  u 

xj'S 

a 

* 

3  —  r 

>g 

t.£ 

«ji 

3  <u 

—  X 

s  £~ 

•7  5 

si  -r. 

»  *- 

3  s 

"c  xf 

StM    C 

"~  *C 

*JT  "5 

^  "•" 

^  y 

v:  c  r. 

^  t^ 

—  > 

0.2 

1002.911 

42.972 

1045.883 

1045.307 

0.57(5 

0.4 

1002.91  1 

85.944 

1088.805 

1087.417 

1.438 

0.6 

1002.911 

128.9  1C 

1131.827 

1130.412 

1.415 

0.8 

1002.K11 

171.888 

1174.799 

1171.596 

3.203 

1.0 

1002.911 

214.860 

1217.771 

1214.209 

3.562 

24 
TABLE  8. 

V 

Temperature  25  degrees.     Sp.  Gr.  of  solid  sugar  =  1.5800. 


"^ 

•s. 

c 

I 

"S 

yo 

2  c 

is 

•^  r—i 

C1 

0 

^  CD  tJ3 

C^   • 

re 

a  os 

Is 

I*; 

O+J  £ 

tt  Q 

'~f~  S 

z  K 

a^-S 

ll 

14,2 

^:  o 

._-,  p 

^  a 

-**"  ? 

---  7 

'A  o  d 

C  > 

0.2 

1002.911 

42.836 

1045.747 

3045.307 

0.440 

0.4 

1002.911 

85.672 

1088.583 

1087.417 

1.116 

0.6 

1002.911 

128.508 

1131.409 

1130.412 

.997 

0.8 

1002.911 

171.344 

1174.255 

1171.596 

2.659 

1.0 

1002.911 

214.180 

1217.090 

1214.209 

2.881 

Tables  9  and  10  contain  the  results  obtained  at  30  degrees. 

TABLE  9. 

Temperature  30  degrees.     Sp.  Gr.  of  solid  sugar  =  1.5813. 


11 

pa  « 

^ 

||l 

II' 

°  !/ 

>c 

|| 

"3  p1 

5«w  c 

g"e 

SO 

&  C 

•^  ^ 

x  -  — 

3  > 

0.2 

1004.314 

42.994 

1047.308 

1046.801 

0.507 

0.4 

1004.314 

85.988 

1090.302 

1089.055 

1.247 

0.6 

1004.314 

128.982 

1132.296 

1132.182 

1.114 

0.8 

1004.314 

171.976 

1176.290 

1173.479 

2.811 

1.0 

1004.314 

214.970 

1219.284 

1216.235 

3.049 

TABLE  10. 

Temperature  30 

degrees. 

Sp.  Gr.  of  solid 

sugar  = 

1.5860 

V 

m 

g 

g 

3 

So 

o 

o 

o 

>  __  ^ 

M 

a 

S'S 

IP 

o 

Is 

^ll 

£1 

S.S 

.5?  a 

3  _2 

!§ 

§J5 

^  c 

ll 

SI 

^«w  C 
9Q  o  ti 

§1 

0.2 

1004.314 

42.860 

1047.174 

1046.801 

0.373 

0.4 

1004.314 

85.720 

1090.034 

1089.055 

0.979 

0.6 

1004.314 

128.580 

1132.894 

1132.182 

0.712 

0.8 

1004.314 

171.440 

1175.754 

1173.479 

2.275 

1.0 

1004.314 

214.300 

1218.614 

1216.235 

2.379 

The  values  of  the  contraction  obtained  at  the  different  tem- 
peratures are  all  brought  together  in  Tables  11  and  12,  in  order 
to  observe  what  takes  place  as  the  temperature  is  raised. 


25 

TABLE  11. 

Sp.  (Jr.  of  sol  i<l  su.tr.Mr  =  l.r.xi::. 


1) 

c 

| 

| 

1 

fl 

-u  — 

1  • 

eS    • 

n 

t  ; 

g-g 

1 

Is 

O  ,j 

II 

ll 

°-M 

u  ^ 

>  - 

w  ej 

u£ 

Q  u 

0.2 

0.832 

0.692 

0.57«; 

0.507 

.325 

0.4 

1.9*9 

1.673 

1.438 

1.247 

.702 

0.6 

2.190 

1.789 

1.415 

1.114 

1.079 

0.8 

4.195 

3.666 

3.203 

2.811 

1.384 

1.0 

4.805 

4.148 

3.562 

3.049 

1.756 

TABLE  12. 
Sp.  Gr.  of  solid  sugar  —  1.5860. 


0.2 

0.696 

0.556 

0.440 

(}.:\i:\ 

.323 

0.4 

1.677 

1.401 

1.116 

0.979 

.698 

0.6 

1.782 

L.381 

.997 

0.712 

1.060 

0.8 

3.651 

3.122 

2.659 

2.275 

1.376 

1.0 

4.12." 

3.468 

2.881 

2.379 

1.756 

A  stud}'  of  the  table  shows  that  as  the  temperature  is  raised, 
the  contraction,  or  the  difference  between  the  sum  of  the 
volumes  of  the  solute  and  solvent  on  the  one  side,  and  the  ob- 
served volume  of  the  solution  on  the  other  side,  diminishes. 
This  decrease  is  not  directly  proportional  to  the  rise  in  tempera- 
ture, but  is  greater  between  15  and  20  degrees  than  it  is  be- 
luccn  20  and  25  or  25  and  30  degrees.  At  each  temperature, 
the  contraction  is  proportional  to  the  concentration,  as  is  also 
the  decrease  in  contraction.  Sufficient  data  is  not  at  hand 
to  pass  final  judgment  on  these  facts,  but  it  appears  that  as  the 
temperature  is  raised,  the  observed  volumes  approaches 
that  of  the  sum  of  the  volumes  of  the  solvent  and  solute. 
Whether  or  not  they  ever  become  equal  remains  for  future 
investi  cations  to  show.  The  two  most  concentrated  so- 


26 

hitions  were  found  to  have  lost  in  rotation  while  they  were 
in  the  bath,  but  lack  of  time  prevented  repetition  of  the  ex- 
periments. The  exact  rotations  in  degrees  are  given  in  Table 
13.  The  first  column  gives  the  rotation  when  the  solution  was 
made  up,  the  second  column,  the  rotation  when  the  apparatus 
was  taken  down  after  the  completion  of  the  experiment,  and  the 
last  column,  the  loss  in  rotation. 


TABLE  13. 


o  c                                     c 

0  £         %  &         %  r< 

•S-3  3s  .2s  ce 

§i  -§!  S^'S  -5 

K  %  ^<S  c-  -*m  &  w-2 

^  2  ~  -  ^  -^  't:  ^  j  P 

0.2  24.85  24.80  0.05 

0.4  48.0  47.8  0.2 

0.6  69.2  69.2  0.00 

0.8  89.0  84.3  4.7 

1.0  107.4  98.8  8.6 


It  is  known1  a  loss  of  one  degree  in  rotation  corresponds,  in 
the  case  of  .9  weight  normal  cane  sugar  solution  at  20  degrees 
C.  to  2.49  grams  of  invert  sugar,  and  in  the  case  of  1.0  weight 
normal  sugar  solution  to  2.53  grams  of  invert  sugar.  This 
correction  could  be  applied  as  a  means  of  ascertaining  the  ex- 
tent of  the  inversion  of  the  cane  sugar;  if  it  could  be  proved 
that  none  of  the  products  of  the  inversion  had  been  converted 
by  fermentation  into  carbon  dioxide  and  water. 

The  expansion  coefficients  for  the  solutions  between  the  dif- 
ferent temperatures  were  also  calculated.  Table  14  contains 
the  expansion  coefficients  between  15  and  20  degrees,  based  on 
the  volumes  of  the  solutions  at  15  degrees  as  unity.  It  also 
contains  the  volume  and  expansion  coefficient  of  air-free  water 
reduced  to  the  same  unit  i.  e.  the  volume  of  water  at  15  degrees. 

1.     Dissertation  of  E.  J.  Hoffman.  190(3. 


27 

TABLE  14. 


§ 


11 

1°» 

"  . 

Is 

2  o> 

SE 

t-i  3 

|i 

—  ^ 

^ 

~  '_ 

fi  'o 

•*i  ° 

^  ;l 

U*  "-- 

^.  ~ 

-—  ^- 

^  0 

Water 

100.4096 

100.4976 

.0880 

.000175 

0.2 

100.2520 

100.3536 

.1017 

.000203 

0.4 

100.4023 

100.5150 

.1128  • 

.000224 

0.6 

100.4419 

100.5637 

.1218 

.000243 

0.8 

100.3826 

100.5130 

.1305 

.000260 

1.0 

100.3220 

100.4605 

.1385 

.000276 

Table  15  contains  the  expansion  coefficients  of  .the  sugar  solu- 
tions, also  air-free  water  between  20  and  25  degrees,  based  on 
the  volumes  at  20  degrees  as  unity. 


TABLE  lo. 


3c 

K  a; 


II 

I 

II 

g| 

11 

Water 

100.4976 

100.6132 

.1156 

.000230 

0.2 

100.3536 

100.4786 

.1249 

.000249 

0.4 

100.5150 

100.6486 

.1335 

.000266 

0.6 

100.5637 

100.7067 

.1430 

.000284 

0.8 

100.5130 

100.6607 

.1477 

.000294 

1.0 

100.4605 

100.6151 

.1546 

.000308 

Table  10  contains  the  expansion  coefficients  of  the  sugar 
solutions,  also  air-free  water  between  25  and  30  degrees,  based 
on  the  volumes  at  25  degrees  as  unity. 


TABLE  36. 


! 

9)  . 

c 

If 

2*3 

0 

§0 

~  5 

C  'o 

^'\ 

O  ^j 

i"i 

ti 
11 

^  £ 

^-  7; 

'•^  r. 

>-H  >• 

—  w 

Water 

100.6132 

100.7.107 

.1375 

.000274 

0.2 

100.4786 

100.6222 

.1436 

.OOOL'SC, 

0.4 

100.6486 

100.8002 

.1516 

.000301 

0.6 

100.7067 

100.8644 

.1577 

.000313 

0.8 

100.6607 

100.8225 

.1618 

.000322 

1.0 

100.6151 

100.7829 

.1678 

.000334 

28 


All  the  coefficients  are  brought  together  in  Table  17  for  the 
sake  of  comparison. 

TABLE  17. 


£1  K 

MS 

Eg 

Water 
0.2 
0.4 
0.6 
0.8 
1.0 


III 

Hi 


.000175 
.000203 
.000224 
.000243 
.000260 
.000276 


.000230 
.000249 
.000266 
.000284 
.000294 
.000308 


.000274 
.000286 
.000301 
.000313 
.000322 
.000334 


In  the  preceeding  expansion  coefficients,  the  ones  obtained  be- 
tween 15  and  20  degrees  are  referred  to  the  volume  of  the  solu- 
tion at  15  degrees  as  unity,  those  between  20  and  25  degrees  are 
referred  to  the  volume  at  20  degrees  as  unity,  and  those  be- 
tween 25  and  30  degrees  are  referred  to  the  volume  at  25  de- 
grees as  unity.  It  seemed  desirable  to  calculate  the  expansion 
coefficients  basing  them  all  on  the  same  unit.  In  the  following, 
then,  the  unit  employed  is  the  volumes  of  the  solutions  at  15 
degrees,  and  in  the  case  of  air-free  water,  the  volume  of  the 
water  at  15  degrees. 

Table  18  contains  the  expansion  coefficients  between  15  and 
20  degrees. 

TABLE  18. 


*ji| 

gtt 

58 

£  = 

3e 

II 

£3 

c 

>  K 

c  e 

%^  ? 

Water 

100.4096 

100.4976 

.0880 

.000175 

0.2 

100.2520 

100.3536 

.1017 

.000203 

0.4 

100.4023 

100.5150 

.1128 

.000224 

0.6 

100.4419 

100.5637 

.1218 

.000243 

0.8 

100.3826 

100.5130 

.1305 

.000260 

1.0 

100.3220 

100.4605 

.1385 

.000276 

29 

Table  1!)  contains  the  expansion  coefficients  between  20  and 
>  dfgm's.  based  on  the  volume  at  15  degrees  as  unity. 

TABLE  19. 


.2  e 


u  E 

=  r 

i» 

If 

If 

£  | 

>** 

>* 

c  c 

£  5 

Water 

]00.4!>7«; 

100.6132 

.1156 

.000230 

0.2 

100.3536 

100.4786 

.1249 

.000249 

0.4 

100.5150 

100.6486 

.1335 

.000266 

0.6 

100.5<  ;:57 

100.7067 

.1430 

.000285 

0.8 

100.5130 

100.6607 

.1477 

.000295 

1.0 

100.4605 

100.6151 

.1546 

.000308 

Table  20  contains  the  expansion  coefficients  between  25  and 
:',<»  de^rese,  based  on  the  volume  at  15  degrees  as  unity. 


TABLE  20. 


Water 

100.6132 

100.7507 

.1375 

.000274 

0.2 

100.4786 

100.6222 

.1436 

.000286 

0.4 

100.6486 

100.8002 

.1516 

.000301 

0.6 

100.7067 

100.8644 

.1577 

.000315 

0.8 

100.6607 

100.8225 

.1618 

.000322 

1.0 

100.6151 

100.7829 

.1678 

.000344 

All  the  expansion  coefficients,  based  on  the  volumes  at  15  de- 
grees, are  brought  together  in  Table  21. 


TABLE  21. 


>  £ 

W.-itcr 
0.2 
0.4 
0.6 
0.8 
1.0 


.000175 
.000203 
.000224 
.000243 
.000260 
.000276 


§0 


I 

.000230 
.000249 
.000266 
.000285 
.000295 


.' 


.000274 
.000286 
.000301 
.000315 
.000322 
.000344 


30 

The  expansion  coefficients  increase  with  the  temperature, 
as  shown  by  the  table.  They  are  also  roughly  proportional  to 
the  concentration,  but  the  results  can  not  be  regarded  as  final 
since  the  0.8  and  0.9  weight  normal  solutions  lost  in  rotation. 
This  portion  of  the  work  will  therefore  have  to  be  repeated. 

The  expansion  coefficients  obtained  for  water  show  practical 
agreement  with  those  given  in  Landolt-Boernstein's  Physik- 
alisch-Chemishe  Tabellen.  so  that  the  apparatus  may  be  re- 
garded as  accurate.  With  apparatus  on  hand,  then,  the  vol- 
umes of  various  solutions  can  be  determined  over  a  consider- 
able range  of  temperature,  and  some  light  may  be  thrown  on 
facts  whose  relation  at  present  is  not  clearly  seen. 


BIOGRAPHY. 

Felton  Samuel  Denser  was  born  .May  111,  lSS<i,  at  Steelton, 
Pennsylvania.  His  early  education  was  obtained  from  the 
public  schools  of  dial  place.  He  entered  Pennsylvania  College 
in  the  fall  of  1905,  and  jjradnated  with  tbe  1».  S.  decree  in 
1909.  In  October,  1909,  he  entered  the  Chemical  Department 
of  .lolins  Hopkins  rnivershy.  His  subordinate  subjects  arc 
IMiysical  Chemistry  and  Applied  Electricity. 


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